This invention relates to a method of and an apparatus for carrying out a chemical reaction involving dehydration in an industrially advantageous manner.
Among organic chemical reactions, there are known a number of reactions involving the formation of water, namely dehydration reactions, such as ketal formation, esterification and alcoholate formation.
In the dehydration reaction system, there exists an equilibrium between the starting material system and the reaction product system. Under the influence of water formed as the reaction proceeds, the progress of the reaction gradually slows down until an equilibrium is reached and the reaction does not proceed any more.
Thus, the equilibrium generally renders it difficult to obtain the desired main products in high yields in the dehydration reaction system.
For this reason, the art has thus far contrived to increase the yields of reaction products by using a reaction solvent in large amounts to thereby dilute relatively the concentration of water formed and thus reduce the influence of the equilibrium on the reaction, by using a variety of dehydrating agents inert to the reaction to thereby remove the water formed out of the system, or by repeating batchwise charging of a reaction solvent and water removal by distillation to thereby decrease the concentration of water formed and reduce the influence of water step by step.
The law of equilibrium teaches that an increase in the yield of a desired main reaction product can be expected when a component of the starting material system, for instance a reaction solvent, is used in a relatively increased amount. This measure, however, cannot be advantageous from the industrial viewpoint since a large quantity of energy is required not only for carrying out the reaction but also for separation and recovery of the solvent after reaction.
Even when the water formed can be removed through the use of a variety of dehydrating agents, their general use is not an easy matter because considerable expenses are incurred for the regeneration or recovery of the dehydrating agents.
For obtaining the desired products in good yields on a commercial scale, it is therefore very important to conduct the reaction while removing the water formed in the dehydration reaction out of the reaction system efficiently.